]> www.pilppa.org Git - linux-2.6-omap-h63xx.git/commitdiff
[IA64] Optional method to purge the TLB on SN systems
authorJack Steiner <steiner@sgi.com>
Tue, 8 May 2007 21:50:43 +0000 (14:50 -0700)
committerTony Luck <tony.luck@intel.com>
Tue, 8 May 2007 21:50:43 +0000 (14:50 -0700)
This patch adds an optional method for purging the TLB on SN IA64 systems.
The change should not affect any non-SN system.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
arch/ia64/kernel/irq_ia64.c
arch/ia64/kernel/smp.c
arch/ia64/sn/kernel/sn2/sn2_smp.c
include/asm-ia64/hw_irq.h
include/asm-ia64/tlbflush.h

index 456f57b087ca78c9b3ddbc7244b125a6657ef8fa..9a5f41be760ba11b933d1532d040c55cc85c740f 100644 (file)
@@ -39,6 +39,7 @@
 #include <asm/machvec.h>
 #include <asm/pgtable.h>
 #include <asm/system.h>
+#include <asm/tlbflush.h>
 
 #ifdef CONFIG_PERFMON
 # include <asm/perfmon.h>
@@ -127,8 +128,10 @@ void destroy_irq(unsigned int irq)
 
 #ifdef CONFIG_SMP
 #      define IS_RESCHEDULE(vec)       (vec == IA64_IPI_RESCHEDULE)
+#      define IS_LOCAL_TLB_FLUSH(vec)  (vec == IA64_IPI_LOCAL_TLB_FLUSH)
 #else
 #      define IS_RESCHEDULE(vec)       (0)
+#      define IS_LOCAL_TLB_FLUSH(vec)  (0)
 #endif
 /*
  * That's where the IVT branches when we get an external
@@ -180,8 +183,11 @@ ia64_handle_irq (ia64_vector vector, struct pt_regs *regs)
        saved_tpr = ia64_getreg(_IA64_REG_CR_TPR);
        ia64_srlz_d();
        while (vector != IA64_SPURIOUS_INT_VECTOR) {
-               if (unlikely(IS_RESCHEDULE(vector)))
-                        kstat_this_cpu.irqs[vector]++;
+               if (unlikely(IS_LOCAL_TLB_FLUSH(vector))) {
+                       smp_local_flush_tlb();
+                       kstat_this_cpu.irqs[vector]++;
+               } else if (unlikely(IS_RESCHEDULE(vector)))
+                       kstat_this_cpu.irqs[vector]++;
                else {
                        ia64_setreg(_IA64_REG_CR_TPR, vector);
                        ia64_srlz_d();
@@ -227,8 +233,11 @@ void ia64_process_pending_intr(void)
          * Perform normal interrupt style processing
          */
        while (vector != IA64_SPURIOUS_INT_VECTOR) {
-               if (unlikely(IS_RESCHEDULE(vector)))
-                        kstat_this_cpu.irqs[vector]++;
+               if (unlikely(IS_LOCAL_TLB_FLUSH(vector))) {
+                       smp_local_flush_tlb();
+                       kstat_this_cpu.irqs[vector]++;
+               } else if (unlikely(IS_RESCHEDULE(vector)))
+                       kstat_this_cpu.irqs[vector]++;
                else {
                        struct pt_regs *old_regs = set_irq_regs(NULL);
 
@@ -260,12 +269,12 @@ void ia64_process_pending_intr(void)
 
 
 #ifdef CONFIG_SMP
-extern irqreturn_t handle_IPI (int irq, void *dev_id);
 
 static irqreturn_t dummy_handler (int irq, void *dev_id)
 {
        BUG();
 }
+extern irqreturn_t handle_IPI (int irq, void *dev_id);
 
 static struct irqaction ipi_irqaction = {
        .handler =      handle_IPI,
@@ -278,6 +287,13 @@ static struct irqaction resched_irqaction = {
        .flags =        IRQF_DISABLED,
        .name =         "resched"
 };
+
+static struct irqaction tlb_irqaction = {
+       .handler =      dummy_handler,
+       .flags =        SA_INTERRUPT,
+       .name =         "tlb_flush"
+};
+
 #endif
 
 void
@@ -303,6 +319,7 @@ init_IRQ (void)
 #ifdef CONFIG_SMP
        register_percpu_irq(IA64_IPI_VECTOR, &ipi_irqaction);
        register_percpu_irq(IA64_IPI_RESCHEDULE, &resched_irqaction);
+       register_percpu_irq(IA64_IPI_LOCAL_TLB_FLUSH, &tlb_irqaction);
 #endif
 #ifdef CONFIG_PERFMON
        pfm_init_percpu();
index 55ddd809b02d47aa72fc7b1f251c851aeffddc40..221de38045604ef1f791a015f61e2a399ca00a89 100644 (file)
 #include <asm/unistd.h>
 #include <asm/mca.h>
 
+/*
+ * Note: alignment of 4 entries/cacheline was empirically determined
+ * to be a good tradeoff between hot cachelines & spreading the array
+ * across too many cacheline.
+ */
+static struct local_tlb_flush_counts {
+       unsigned int count;
+} __attribute__((__aligned__(32))) local_tlb_flush_counts[NR_CPUS];
+
+static DEFINE_PER_CPU(unsigned int, shadow_flush_counts[NR_CPUS]) ____cacheline_aligned;
+
+
 /*
  * Structure and data for smp_call_function(). This is designed to minimise static memory
  * requirements. It also looks cleaner.
@@ -248,6 +260,62 @@ smp_send_reschedule (int cpu)
        platform_send_ipi(cpu, IA64_IPI_RESCHEDULE, IA64_IPI_DM_INT, 0);
 }
 
+/*
+ * Called with preeemption disabled.
+ */
+static void
+smp_send_local_flush_tlb (int cpu)
+{
+       platform_send_ipi(cpu, IA64_IPI_LOCAL_TLB_FLUSH, IA64_IPI_DM_INT, 0);
+}
+
+void
+smp_local_flush_tlb(void)
+{
+       /*
+        * Use atomic ops. Otherwise, the load/increment/store sequence from
+        * a "++" operation can have the line stolen between the load & store.
+        * The overhead of the atomic op in negligible in this case & offers
+        * significant benefit for the brief periods where lots of cpus
+        * are simultaneously flushing TLBs.
+        */
+       ia64_fetchadd(1, &local_tlb_flush_counts[smp_processor_id()].count, acq);
+       local_flush_tlb_all();
+}
+
+#define FLUSH_DELAY    5 /* Usec backoff to eliminate excessive cacheline bouncing */
+
+void
+smp_flush_tlb_cpumask(cpumask_t xcpumask)
+{
+       unsigned int *counts = __ia64_per_cpu_var(shadow_flush_counts);
+       cpumask_t cpumask = xcpumask;
+       int mycpu, cpu, flush_mycpu = 0;
+
+       preempt_disable();
+       mycpu = smp_processor_id();
+
+       for_each_cpu_mask(cpu, cpumask)
+               counts[cpu] = local_tlb_flush_counts[cpu].count;
+
+       mb();
+       for_each_cpu_mask(cpu, cpumask) {
+               if (cpu == mycpu)
+                       flush_mycpu = 1;
+               else
+                       smp_send_local_flush_tlb(cpu);
+       }
+
+       if (flush_mycpu)
+               smp_local_flush_tlb();
+
+       for_each_cpu_mask(cpu, cpumask)
+               while(counts[cpu] == local_tlb_flush_counts[cpu].count)
+                       udelay(FLUSH_DELAY);
+
+       preempt_enable();
+}
+
 void
 smp_flush_tlb_all (void)
 {
index 601747b1e22aa82c54dba040f6cb31034436facf..5d318b579fb1b01b3fb4f89c95c849a31d2939aa 100644 (file)
@@ -46,6 +46,9 @@ DECLARE_PER_CPU(struct ptc_stats, ptcstats);
 
 static  __cacheline_aligned DEFINE_SPINLOCK(sn2_global_ptc_lock);
 
+/* 0 = old algorithm (no IPI flushes), 1 = ipi deadlock flush, 2 = ipi instead of SHUB ptc, >2 = always ipi */
+static int sn2_flush_opt = 0;
+
 extern unsigned long
 sn2_ptc_deadlock_recovery_core(volatile unsigned long *, unsigned long,
                               volatile unsigned long *, unsigned long,
@@ -76,6 +79,8 @@ struct ptc_stats {
        unsigned long shub_itc_clocks;
        unsigned long shub_itc_clocks_max;
        unsigned long shub_ptc_flushes_not_my_mm;
+       unsigned long shub_ipi_flushes;
+       unsigned long shub_ipi_flushes_itc_clocks;
 };
 
 #define sn2_ptctest    0
@@ -121,6 +126,18 @@ void sn_tlb_migrate_finish(struct mm_struct *mm)
                flush_tlb_mm(mm);
 }
 
+static void
+sn2_ipi_flush_all_tlb(struct mm_struct *mm)
+{
+       unsigned long itc;
+
+       itc = ia64_get_itc();
+       smp_flush_tlb_cpumask(mm->cpu_vm_mask);
+       itc = ia64_get_itc() - itc;
+       __get_cpu_var(ptcstats).shub_ipi_flushes_itc_clocks += itc;
+       __get_cpu_var(ptcstats).shub_ipi_flushes++;
+}
+
 /**
  * sn2_global_tlb_purge - globally purge translation cache of virtual address range
  * @mm: mm_struct containing virtual address range
@@ -154,7 +171,12 @@ sn2_global_tlb_purge(struct mm_struct *mm, unsigned long start,
        unsigned long itc, itc2, flags, data0 = 0, data1 = 0, rr_value, old_rr = 0;
        short nasids[MAX_NUMNODES], nix;
        nodemask_t nodes_flushed;
-       int active, max_active, deadlock;
+       int active, max_active, deadlock, flush_opt = sn2_flush_opt;
+
+       if (flush_opt > 2) {
+               sn2_ipi_flush_all_tlb(mm);
+               return;
+       }
 
        nodes_clear(nodes_flushed);
        i = 0;
@@ -189,6 +211,12 @@ sn2_global_tlb_purge(struct mm_struct *mm, unsigned long start,
                return;
        }
 
+       if (flush_opt == 2) {
+               sn2_ipi_flush_all_tlb(mm);
+               preempt_enable();
+               return;
+       }
+
        itc = ia64_get_itc();
        nix = 0;
        for_each_node_mask(cnode, nodes_flushed)
@@ -256,6 +284,8 @@ sn2_global_tlb_purge(struct mm_struct *mm, unsigned long start,
                        }
                        if (active >= max_active || i == (nix - 1)) {
                                if ((deadlock = wait_piowc())) {
+                                       if (flush_opt == 1)
+                                               goto done;
                                        sn2_ptc_deadlock_recovery(nasids, ibegin, i, mynasid, ptc0, data0, ptc1, data1);
                                        if (reset_max_active_on_deadlock())
                                                max_active = 1;
@@ -267,6 +297,7 @@ sn2_global_tlb_purge(struct mm_struct *mm, unsigned long start,
                start += (1UL << nbits);
        } while (start < end);
 
+done:
        itc2 = ia64_get_itc() - itc2;
        __get_cpu_var(ptcstats).shub_itc_clocks += itc2;
        if (itc2 > __get_cpu_var(ptcstats).shub_itc_clocks_max)
@@ -279,6 +310,11 @@ sn2_global_tlb_purge(struct mm_struct *mm, unsigned long start,
 
        spin_unlock_irqrestore(PTC_LOCK(shub1), flags);
 
+       if (flush_opt == 1 && deadlock) {
+               __get_cpu_var(ptcstats).deadlocks++;
+               sn2_ipi_flush_all_tlb(mm);
+       }
+
        preempt_enable();
 }
 
@@ -425,24 +461,42 @@ static int sn2_ptc_seq_show(struct seq_file *file, void *data)
 
        if (!cpu) {
                seq_printf(file,
-                          "# cpu ptc_l newrid ptc_flushes nodes_flushed deadlocks lock_nsec shub_nsec shub_nsec_max not_my_mm deadlock2\n");
-               seq_printf(file, "# ptctest %d\n", sn2_ptctest);
+                          "# cpu ptc_l newrid ptc_flushes nodes_flushed deadlocks lock_nsec shub_nsec shub_nsec_max not_my_mm deadlock2 ipi_fluches ipi_nsec\n");
+               seq_printf(file, "# ptctest %d, flushopt %d\n", sn2_ptctest, sn2_flush_opt);
        }
 
        if (cpu < NR_CPUS && cpu_online(cpu)) {
                stat = &per_cpu(ptcstats, cpu);
-               seq_printf(file, "cpu %d %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld\n", cpu, stat->ptc_l,
+               seq_printf(file, "cpu %d %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld\n", cpu, stat->ptc_l,
                                stat->change_rid, stat->shub_ptc_flushes, stat->nodes_flushed,
                                stat->deadlocks,
                                1000 * stat->lock_itc_clocks / per_cpu(cpu_info, cpu).cyc_per_usec,
                                1000 * stat->shub_itc_clocks / per_cpu(cpu_info, cpu).cyc_per_usec,
                                1000 * stat->shub_itc_clocks_max / per_cpu(cpu_info, cpu).cyc_per_usec,
                                stat->shub_ptc_flushes_not_my_mm,
-                               stat->deadlocks2);
+                               stat->deadlocks2,
+                               stat->shub_ipi_flushes,
+                               1000 * stat->shub_ipi_flushes_itc_clocks / per_cpu(cpu_info, cpu).cyc_per_usec);
        }
        return 0;
 }
 
+static ssize_t sn2_ptc_proc_write(struct file *file, const char __user *user, size_t count, loff_t *data)
+{
+       int cpu;
+       char optstr[64];
+
+       if (copy_from_user(optstr, user, count))
+               return -EFAULT;
+       optstr[count - 1] = '\0';
+       sn2_flush_opt = simple_strtoul(optstr, NULL, 0);
+
+       for_each_online_cpu(cpu)
+               memset(&per_cpu(ptcstats, cpu), 0, sizeof(struct ptc_stats));
+
+       return count;
+}
+
 static struct seq_operations sn2_ptc_seq_ops = {
        .start = sn2_ptc_seq_start,
        .next = sn2_ptc_seq_next,
@@ -458,6 +512,7 @@ static int sn2_ptc_proc_open(struct inode *inode, struct file *file)
 static const struct file_operations proc_sn2_ptc_operations = {
        .open = sn2_ptc_proc_open,
        .read = seq_read,
+       .write = sn2_ptc_proc_write,
        .llseek = seq_lseek,
        .release = seq_release,
 };
index 27f9df6b914539401c26421ce0bb38d970ef0081..c054d7a9aaa771cfb5743052c76fdca953b4aa69 100644 (file)
@@ -66,6 +66,7 @@ extern int ia64_last_device_vector;
 #define IA64_PERFMON_VECTOR            0xee    /* performanc monitor interrupt vector */
 #define IA64_TIMER_VECTOR              0xef    /* use highest-prio group 15 interrupt for timer */
 #define        IA64_MCA_WAKEUP_VECTOR          0xf0    /* MCA wakeup (must be >MCA_RENDEZ_VECTOR) */
+#define IA64_IPI_LOCAL_TLB_FLUSH       0xfc    /* SMP flush local TLB */
 #define IA64_IPI_RESCHEDULE            0xfd    /* SMP reschedule */
 #define IA64_IPI_VECTOR                        0xfe    /* inter-processor interrupt vector */
 
index cf9acb9bb1fb69b7744f4e40081ad1bdcf8061b0..e37f9fbf33af8babd7406b648219a1dca48bc152 100644 (file)
@@ -27,9 +27,11 @@ extern void local_flush_tlb_all (void);
 #ifdef CONFIG_SMP
   extern void smp_flush_tlb_all (void);
   extern void smp_flush_tlb_mm (struct mm_struct *mm);
+  extern void smp_flush_tlb_cpumask (cpumask_t xcpumask);
 # define flush_tlb_all()       smp_flush_tlb_all()
 #else
 # define flush_tlb_all()       local_flush_tlb_all()
+# define smp_flush_tlb_cpumask(m) local_flush_tlb_all()
 #endif
 
 static inline void
@@ -94,6 +96,15 @@ flush_tlb_pgtables (struct mm_struct *mm, unsigned long start, unsigned long end
         */
 }
 
+/*
+ * Flush the local TLB. Invoked from another cpu using an IPI.
+ */
+#ifdef CONFIG_SMP
+void smp_local_flush_tlb(void);
+#else
+#define smp_local_flush_tlb()
+#endif
+
 #define flush_tlb_kernel_range(start, end)     flush_tlb_all() /* XXX fix me */
 
 #endif /* _ASM_IA64_TLBFLUSH_H */